1. Field of the Invention
The present invention relates to a power supply adapter and a power supply system to supply electric power to an electronic device and/or to a secondary battery mounted on the electronic device.
This application claims priority of Japanese Patent Application No. 2003-191358, filed on Jul. 3, 2003, the entirety of which is incorporated by reference herein.
2. Description of the Related Art
In recent years, portable electronic devices are spreading such as notebook personal computers, portable cellular phones, camera-mounted VTRs (Video Tape Recorders), and PDAs (Personal Digital Assistants). These portable electronic devices are mounted with secondary batteries such as lithium ion secondary batteries and nickel hydride secondary batteries. These batteries feature light weight and high energy density, and are capable of charge and discharge. The electronic devices operate using these secondary batteries as drive power supplies.
When the secondary battery power is used up completely, the portable electronic devices are supplied with drive power from an external power supply, for example, via power supply adapters such as AC adapters and the like. When supplied from the external power supply via power supply adapters and the like, the electric power directly drives a portable electronic device or charges a secondary battery mounted in the device. Accordingly, portable electronic devices become unusable when the secondary batteries are completely consumed at a place where there is not available an external power supply, i.e., a power receptacle capable of supplying power.
A solution to this problem is, for example, a fuel cell that can generate power by means of electrochemical reaction where no power receptacle is available. Specifically, there are available personal computers and the like mounted with fuel cells (Jpn. Pat. Appln. Laid-Open Publication No. 2002-49440).
Example fuel cells include PEFC (Polymer Electrolyte Fuel Cell), DMFC (Direct Methanol Fuel Cell), and the like. To generate power, these fuel cells use hydrogen, alcoholic substances, and the like as fuel, oxidize the fuel at cathodes, and deoxidize oxygen and the like in the air and the like at anodes.
If a portable electronic device is equipped with the fuel cell as a drive power supply, however, an inlet needs to be provided to take the fuel for power generation into the cell. Further, pipe laying is needed to circulate the fuel in the cell. Moreover, an outlet or the like needs to be provided to exhaust carbon dioxide, water, vapor, and the like because these are generated as reaction products after power generation due to the electrochemical reaction. When chemical compounds such as hydrocarbon and the like are used as the fuel, a reformer or the like is needed to reform the chemical compound so as to generate hydrogen from the chemical compound.
When the portable electronic device uses a fuel cell as the drive power supply, it is difficult to make the portable electronic device small and lightweight.
Further, when the portable electronic device uses a fuel cell as the drive power supply, the fuel cell generates much heat due to power generation according to the electrochemical reaction. The portable electronic device may malfunction due to heat generated from the fuel cell.